Conventionally, a toner employed for the development in electrophotograpy has been prepared generally by a method in which a colorant (carbon black, magnetic powder, pigment, etc.), a charge control agent and other additives are melt kneaded in a thermoplastic resin, pulverized and classified.
In order to overcome various disadvantages of the toner prepared by the pulverization method, preparation methods such as an emulsion polymerization method, a suspension polymerization method, etc. have been developed. (Japanese Patent Publication Nos. 36-10231, 47-518305, 51-14895, etc.)
However, these conventional toners have various disadvantages. There have been problems specially on the stability of charge amount and charge rising at the repeated use.